Polarization filter gives many new opportunities (10.06.2016)
Text and photos: Aivar Pihelgas
Polarization filters or “polas“ as photographers affectionately call them, are one of the most popular type of filters in today’s digital photography era. The effect of the polarization filter is almost impossible to create during digital post-processing. While using this filter (mostly during outdoor photography), you need to consider that the dark grey glass of the filter reduces the light that reaches the lens from 1.5 to 2 steps.
There are two types of polarization filters: circular (circular polarization) and linear. It is recommended to use circular polarization filters in today’s cameras because this type of filter suits better with the light-metering and autofocus of the DSLR cameras.
How does this filter work? The light waves oscillate in many different planes. The polarization filter only lets through waves oscillating in one plane, other are reflected back from the filter surface. By rotating the filter elements, it is possible to make the colour of the sky darker, lose the reflections from the water surface and make colours brighter. When using this filter in front of the DSLR camera lens, you can make sure that it works and see the range of the effect before the actual shoot. Try photographing landscape with polarization filter. The effect of the filter is not the same in every direction. The sky darkens the most when the sun is behind the photographer. When you rotate the filter through the lens, look through the lens and see when you get the effect you were looking for.
With lenses that have shorter focal length and extreme wide angle, you might end up having the sky darker in a certain area and instead of the desired effect you get a dark blue spot in the sky with fading edges. With a totally cloudless sky (especially in the mountains), you might even get blackish blue sky as a result. That is why; the polarization filter should be used with caution for not ending up with photos that have unnatural colours and light
When photographing landscape, we notice that the greenness of the plants gets deeper and the colours become brighter. One reason behind this is the fact that the leaves of the plants are often covered with a layer of wax and the polarization filter enables to eliminate part of the light waves reflected from the surface of the plant
The effect of losing the reflections from water surface depends on the angle of the falling light. If the light falls under the right angle (maximum effect is reached with the angle of 40-45 degrees), it is possible to lose the reflection of sky from the water surface and you can see the bed of the water body on the photo. When we lose the reflection of the sky from the car windows, we are able to see who is behind the wheel. Polarization filter does not work when photographing shiny metals but the interesting thing is that it does work when the surface is varnished or slightly oxidized (aluminium, copper).